Maitland, who appeared somewhat agitated by her recital, said to her:  “After the exaction of such a promise you have, of course, no doubt that your father was the victim of a mental malady—­at least, at such times as those of which you speak?”

Gwen replied deliberately:  “Indeed, I have grave doubts.  My father was possessed by a strange conviction, but I never saw anything which impressed me as indicating an unsound mind.  I am, of course, scarcely fitted to judge in such matters.”

Maitland’s face darkened as he asked:  “You would not have me infer that you would consider your promise in any sense binding?”

“And why not?” she ejaculated in astonishment.

“Because,” he continued, “the request is so unnatural as to be in itself sufficient evidence that it was not made by a man in his right mind.”

“I cannot agree with you as to my father’s condition,” Gwen replied firmly; “yet you may be right; I only know that I, at least, was in my right mind, and that I promised.  If it cost me my life to keep that pledge, I shall not hesitate a moment.  Have you forgotten that my father’s last words were, ’remember your promise’?” She glanced up at Maitland as she said this, and started a little as she saw the expression of pain upon his face.  “I seem to you foolishly deluded,” she said apologetically; “and you are displeased to see that my purpose is not shaken.  Think of all my father was to me, and then ask yourself if I could betray his faith.  The contemplation of the subject is painful at best; its realisation may, from the standpoint of a sensitive woman, be fraught with unspeakable horror, —­I dare not think of it!  May we not change the subject?”

For a long time Maitland did not speak, and I forbore to break the silence.  At last he said:  “Let us hope, if the supposed assassin be taken, the discovery may be made by someone worthy the name of man—­someone who will not permit you to sacrifice either yourself or your money.”  Gwen glanced at him quickly, for his voice was strangely heavy and inelastic, and an unmistakable gloom had settled upon him.  I thought she was a little startled, and I was considering if I had not better call her aside and explain that he was subject to these moods, when he continued, apparently unaware of the impression he had made:  “Do you realise how strong a case of suicide the authorities have made out?  Like all of their work it has weak places.  We must search these in order to overthrow their conclusion.  The insurance policies they were ‘too busy’ to read we must peruse.  Then, judging from your story, there seems little doubt that your father has left some explanation of affairs hitherto not confided to you—­some document which he has reserved for your perusal after his death.  No time should be lost in settling this question.  The papers may be here, or in the hands of his attorney.  Let us search here first.”

“His private papers,” Gwen said, rising to lead the way, “are in his desk in the study.”